The invention relates to a method for producing a cuvette or a receptacle vessel for liquid or gaseous media for spectroscopic, qualitative, and/or quantitative analysis or measurement having a measuring region or measuring gap that can be penetrated by radiation and is made from plastic by way of injection molding, with a multi-part injection mold, comprising in the interior the contour of the cuvette or the receptacle vessel with its opening and measuring gap, is first filled with liquid plastic in an injection molding device and after the plastic has set the mold is opened and the cuvette is removed, with in the mold the interior longitudinal cavity and the measuring gap are formed and limited at the inside by a contour core, which during the molding process initially is held by a support.
Such cuvettes made from plastic, but also from quartz glass, are known in various shapes and dimensions, particularly with regard to the thickness of the measuring gap, also called layer thickness. For example, a plastic cuvette is known from DE 198 26 470 A1 having a particular embodiment, comprising two pairs of opposite coplanar windows in order to allow different layer thicknesses.
A layer thickness as low as possible, i.e. a measuring gap with a thickness as low as possible, results in a considerable shortening of the radiation path, which is advantageous for the accuracy of the measurement.
In quartz cuvettes, layer thicknesses of one millimeter or less are possible due to the method of production, however, producing plastic cuvettes with a layer thickness of less than two millimeters was previously impossible so that either a relatively high layer thickness had to be accepted or a very expensive quartz cuvette had to be used, which is not suitable for single use, though, due to its high production costs.